Given the apparent discrepancy in the expression of CCR4 on IL-17+ synovial T cells compared with that on IL-17+ peripheral blood T cells and the recent demonstration that cells with a CCR6+,CCR4– phenotype may include Th1 cells that also produce IL-17, we hypothesized that synovial IL-17+ T cells in JIA would include a population of cells that secrete both IL-17 and IFNγ. This evidence concerns the gene CCR4 and juvenile idiopathic arthritis.